A jury has begun deliberations in the federal death penalty trial of Boston Marathon bomber Dzhokhar Tsarnaev.

Jurors began considering 30 charges against Tsarnaev on Tuesday morning. They heard closing arguments Monday from prosecutors and Tsarnaev's lawyers, and instructions from Judge George O'Toole Jr.

Since Tsarnaev's lawyer admitted he participated in the deadly attack, Tsarnaev's conviction is a near certainty. After the jury reaches a verdict, the same jurors will hear additional evidence in a second phase of the trial to determine whether Tsarnaev should spend the rest of his life in prison or be executed for his crimes.